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dc.contributor.supervisor Dr Trust Beta (Food Science) en
dc.contributor.author Hambira, Chipo
dc.date.accessioned 2010-01-11T15:57:08Z
dc.date.available 2010-01-11T15:57:08Z
dc.date.issued 2010-01-11T15:57:08Z
dc.identifier.uri http://hdl.handle.net/1993/3841
dc.description.abstract Phytochemicals found in grains complement those found in fruits and vegetables. These phytochemicals, though minor compounds, contribute to the antioxidant properties which are related to the health benefits associated with the consumption of whole grain. In this thesis project, nine barley genotypes of diverse origin namely CI2230 from Nepal, CI1248 from Israel, 3 Peruvian genotypes; Peru 3, Peru 16 and Peru 35, Hokuto Hadaka from Japan, EX116; a cross between Moroccan and Canadian genotype, EX83; a cross between two Canadian genotypes and EX127; a cross between Canadian and German genotypes were studied. The genotypes were categorized based on appearance into purple, black and yellow grains. Phenolic acids and flavonoids were identified and quantified in these diverse genotypes using HPLC-ESI-MS analysis. The main classes of dietary flavonoids studied in the barleys were anthocyanins and flavan-3-ols. Phenolic acids were identified and quantified (p-coumaric, ferulic, sinapic, caffeic, vanillic). Three ferulic acid dehydrodimers (8-0-4’ DFA, 8-5’ benzofuran form and 5-5’ DFA) were also identified. The most abundant dimeric flavan-3-ols were procyanidins B3 and prodelphinidin B3. The monomeric unit, (+)-catechin, was the most abundant while catechin glucoside (m/z 451) was also identified. Among the Peruvian genotypes, Peru 16 and Peru 35 exhibited relatively high levels of total PA content. Total phenolic content and antioxidant activities of methanolic, acetone and alkali hydrolyzed extracts of the nine barley genotypes was determined by the Folin- Ciocalteau assay, DPPH radical scavenging assay and oxygen radical absorbance capacity (ORAC assay).The acetone extract exhibited the highest antioxidant capacity using all the methods of analysis. Furthermore, dark colored grains were found to exhibit higher contents of phenolic compounds. The phenolic acids, PAs and anthocyanins identified and quantified had significant contribution to the overall antioxidant capacity of the barley whole grain. Four hull-less genotypes namely CI2230, EX127, CI1248 and Peru 35 were further partially sprouted to establish the effects of sprouting on phenolic acid composition. Partial sprouting was observed to significantly increase the soluble conjugated phenolic acids. The barley genotypes studied were found to contain different quantities of phytochemicals and had high proanthocyanidin content thereby rendering them as alternative sources of antioxidants. Barley sprouts present a possible novel food ingredient with improved properties such as phenolic acid composition and other benefits such as easier incorporation into food products under development. en
dc.format.extent 1295972 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject Barley en
dc.subject Proanthocyanidins en
dc.subject Phenolic Acids en
dc.subject Phenolic Compunds en
dc.subject Anthocyanins en
dc.subject Antioxidant Activity en
dc.subject Grains en
dc.subject ORAC en
dc.subject DPPH en
dc.subject Total phenolic content en
dc.title Proanthocyanidins, anthocyanins and phenolic acids in food barleys of diverse origin en
dc.type info:eu-repo/semantics/masterThesis
dc.degree.discipline Food Science en
dc.contributor.examiningcommittee Dr Gary Fulcher (Food Science), Dr Mohammed Moghadasian (Human Nutritional Sciences) en
dc.degree.level Master of Science (M.Sc.) en
dc.description.note February 2010 en


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